SpringMvc 传参类型问题?报错

最一开始做了一个普通的表单提交。

没问题，后来多了一个日期类型，如果页面填了，保存没，问题，为空，保存时会报类型无法转换的错误，查阅资料后，在基类controller中加入

/** 
     * 用于处理Date类型参数处理
     * @return 
     */  
    @InitBinder  
    protected  void initBinder(WebDataBinder binder) {  
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");  
        binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, true));  
 


    }

我用同样的方法，

//        binder.registerCustomEditor(Float.class, new CustomNumberEditor(Float.class, false));  
//        binder.registerCustomEditor(Integer.class, new CustomNumberEditor(Integer.class, false));  
//        binder.registerCustomEditor(Double.class, new CustomNumberEditor(Double.class, false));

不管怎么样都是不行，这是为什么呢？

填了保存正常，为空是就报错：

org.springframework.validation.BeanPropertyBindingResult: 1 errors
Field error in object 'page_person' on field 'sg': rejected value []; codes [typeMismatch.page_person.sg,typeMismatch.sg,typeMismatch.float,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [page_person.sg,sg]; arguments []; default message [sg]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'float' for property 'sg'; nested exception is java.lang.NumberFormatException: empty String]
org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors
Field error in object 'page_person' on field 'sg': rejected value []; codes [typeMismatch.page_person.sg,typeMismatch.sg,typeMismatch.float,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [page_person.sg,sg]; arguments []; default message [sg]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'float' for property 'sg'; nested exception is java.lang.NumberFormatException: empty String]

跪求大神，在线等

补controller代码：

/**
	 * add、update
	 * @param czPerson
	 * @param person
	 * @return
	 */
	@ResponseBody
	@RequestMapping(value = "/add")
	public String add(@ModelAttribute Page_person person,@ModelAttribute Page_person_cz czPerson) {
		if(StringSimple.isNullOrEmpty(person.getId())){//如果是新增
			if(person_czService.noExist(person.getZjhm())){
				return JsonSimple.toJSONString(Utils.createMsg("fail", "证件号码已经存在！", false));
			}
			person_czService.add(person, czPerson);
		}else{//修改
			czPerson.setId(request.getParameter("czid"));
			czPerson.setPersonid(person.getId());
			person_czService.update(person, czPerson);
		}
		return JsonSimple.toJSONString(Utils.createMsg("success", "保存成功！", true));
	}